US5164829A - Scanning velocity modulation type enhancement responsive to both contrast and sharpness controls - Google Patents

Scanning velocity modulation type enhancement responsive to both contrast and sharpness controls Download PDF

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Publication number
US5164829A
US5164829A US07/709,871 US70987191A US5164829A US 5164829 A US5164829 A US 5164829A US 70987191 A US70987191 A US 70987191A US 5164829 A US5164829 A US 5164829A
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United States
Prior art keywords
outline
sharpness
contrast
picture
signal
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Expired - Lifetime
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US07/709,871
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English (en)
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Michio Wada
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WADA, MICHIO
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/30—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical otherwise than with constant velocity or otherwise than in pattern formed by unidirectional, straight, substantially horizontal or vertical lines
    • H04N3/32—Velocity varied in dependence upon picture information

Definitions

  • the present invention relates to an outline compensation apparatus for providing a controlled degree of enhancement of boundaries between regions of differing brightness in a picture displayed by a television receiver.
  • circuits for effecting a controlled degree of enhancement of the boundaries between adjacent regions which are of mutually different brightness Such circuits of a television receiver will be collectively referred to in the following as an outline compensation apparatus.
  • outline enhancement is usually executed by a velocity modulation circuit, which varies the horizontal scanning velocity of the electron beam of the CRT such as to make the transitions between different regions of the displayed picture become more abrupt, to thereby apply compensation for various signal processing effects which tend to cause the transitions to become gradual.
  • Such outline enhancement results in an apparent increase in sharpness of definition of these boundaries, as seen by the viewer.
  • edge enhancement results in an apparent increase in sharpness of definition of these boundaries, as seen by the viewer.
  • To control such a velocity modulation circuit it is necessary to detect the outlines, i.e. boundaries between regions of different brightness, by detecting sudden changes in amplitude of the luminance signal component of the television signal. This is usually achieved by amplifying and then differentiating the luminance signal, at the point in the television signal path where the chroma signal and luminance signal are separated from the composite video signal (e.g. by means of a comb filter).
  • the luminance signal is subjected to various processing to modify the level of contrast and degree of sharpness of definition of the picture, before being finally applied to drive the cathode of the CRT.
  • the luminance signal that is used for the purposes of outline detection is essentially different from the luminance signal which is applied to the cathode of the CRT.
  • the outline compensation apparatus will continue to apply the same amount of outline enhancement. Since a relatively high degree of outline enhancement contributes to an increased degree of (visually perceived) overall sharpness of definition in the displayed picture, the operation of the outline compensation apparatus in that case will again act to reduce the effectiveness of the reduction of contrast that is desired by the user.
  • the input signal to the outline detection circuit will be at a position (i.e. along the circuit path extending from the point of separation of the chroma and luminance signals to the point of connection to the CRT cathode) that is very close to the CRT.
  • the delay time between the time at which the outline compensation apparatus receives the luminance signal and the time at which the signal reaches the cathode of the CRT will be very short.
  • phase matching will be required for both luminance and chroma components, and will result in increased manufacturing cost, due to the need to incorporate suitable delay elements.
  • the present invention provides an outline compensation apparatus which functions such that an amount of outline enhancement that is effected by the apparatus is modified in accordance with either or both of the level of a contrast adjustment signal, which can be varied by the user to determine a degree of contrast in a displayed picture, and the level of a sharpness adjustment signal, which can be varied by the user to determine a degree of sharpness of definition in the displayed picture.
  • the levels of the contrast adjustment signal and the sharpness adjustment signal will in general be respective DC voltage levels, and these are combined to obtain a limiter control voltage that is applied to an amplitude limiter circuit.
  • the amplitude limiter circuit acts to limit the amplitude of an input signal that is supplied to a velocity modulation circuit from an outline detection circuit, with the amplitude limit value being varied in accordance with the limiter control voltage.
  • FIG. 1 is a general circuit block diagram of an embodiment of an outline compensation apparatus according to the present invention.
  • FIG. 2 is a circuit diagram showing details of a diode limiter circuit in the circuit of FIG. 1.
  • FIG. 1 is a general circuit block diagram of an embodiment of an outline compensation apparatus according to the present invention, in which an input luminance signal (which has been derived in a television receiver circuit, not shown in the drawings, and has not yet been subjected to contrast adjustment or sharpness adjustment processing) is amplified by an amplifier circuit 1, then is inputted to a differentiator circuit 2 to be differentiated, for thereby detecting points in the luminance signal which correspond to outlines in the picture that is represented by that signal. The output signal resulting from this detection is then amplified by an amplifier circuit 3, then is inputted to a drive circuit 4, to be supplied to a output circuit 7 which drives a velocity modulation coil 8.
  • an input luminance signal (which has been derived in a television receiver circuit, not shown in the drawings, and has not yet been subjected to contrast adjustment or sharpness adjustment processing) is amplified by an amplifier circuit 1, then is inputted to a differentiator circuit 2 to be differentiated, for thereby detecting points in the luminance signal which correspond to outlines in the picture that
  • the velocity modulation coil 8 is located on the CRT, and is positioned for applying velocity modulation to the electron beam along the horizontal scanning direction, in accordance with an amplitude of drive current that is produced from the output circuit 7, such as to produce outline enhancement of a picture displayed by the CRT.
  • the level of current flow in the velocity modulation coil 8 is detected and a signal indicative of that level is transferred through a feedback limiter circuit 6 back to the amplifier circuit 3, for limiting the maximum amplitude of velocity modulation that is applied by to the electron beam.
  • amplitude of velocity modulation is limited (within a range of amplitudes which is lower than a level of amplitude at which limiting action by feedback from the feedback limiter circuit 6 begins) by a diode limiter circuit 5 which is coupled to a point in the circuit path of the luminance signal after the input terminal of the amplifier circuit 3, e.g. to the output terminal of the amplifier circuit 3.
  • the actual value of amplitude to which the output signal from the amplifier circuit 3 is limited by the action of the diode limiter circuit 5, at any particular time, is determined by the level of a limit control signal 24 which is applied to the diode limiter circuit 5.
  • the amplifier circuit 1, differentiator circuit 2 and amplifier 3 will be considered to constitute, in combination, an outline detection circuit, while the drive circuit 4, output circuit 7 and coil 8 will be considered to constitute, in combination, a velocity modulation circuit.
  • FIG. 2 shows an example of a detailed circuit configuration for the diode limiter circuit 5 of FIG. 1.
  • a the output signal from the amplifier circuit 3 is transferred through a capacitor 9 to the junction of two diodes 10, 11, with a chain of resistors 12, 13, 14, 15 being connected between an input terminal 18 and ground potential and with the cathode of one of the diodes 10, 11 being connected to the junction of the resistors 12, 13 and the anode of the other one of the diodes being connected to the junction of resistors 14 and 15.
  • the junctions of resistors 12, 13 and 14, 15 are connected via respective capacitors 16, 17 to ground potential.
  • the circuit of FIG. 2 would be equally applicable to a prior art outline compensation apparatus, in which the output signal amplitude from the amplifier circuit 3 is limited to a fixed value. That is to say, in such a prior art outline compensation apparatus, the input terminal 18 of the diode limiter circuit 5 would be fixedly connected to a DC voltage which determines the amplitude limit value, i.e. with the upper limit of the output signal voltage amplitude from the amplifier circuit 3 being substantially equal to the voltage appearing at the junction of the resistors 12, 13 and the lower limit of that output signal voltage amplitude being substantially equal to the voltage appearing at the junction of the resistors 14, 15.
  • each of the capacitors 16 and 17 is made sufficiently high to ensure that effective limiting of the amplitude of the differentiated output voltage pulses produced from the amplifier circuit 3 will occur, when that differentiated voltage amplitude becomes higher than the upper limit value or becomes lower than the lower limit value.
  • the waveform of the output signal from the amplifier circuit 3 is held at a substantially constant amplitude.
  • the voltage 24 that is applied to the input terminal 18 in FIG. 2 is varied in accordance with a combination of the degree of contrast adjustment and the degree of sharpness adjustment that is currently being applied to the luminance signal prior to that signal being supplied to the cathode of the CRT.
  • a contrast adjustment voltage 19 and a sharpness adjustment voltage 20 are generated within the television receiver circuit, which are applied through respective resistors 21 and 22 to a junction of these resistors with a third resistor 23 which is connected to ground potential.
  • the aforementioned limit control voltage 24 is thereby produced at that junction.
  • the respective levels of the contrast adjustment voltage 19 and the sharpness adjustment voltage 20 are varied under the control of the user, i.e.
  • the microcomputer 25 determines optimum values for the contrast adjustment voltage 19 and sharpness adjustment voltage 20 respectively, in accordance with these input signals generated by the user, such as to maintain satisfactory picture quality while effecting desired changes in picture contrast and/or sharpness of definition. That is to say, the contrast adjustment voltage 19 and sharpness adjustment voltage 20 are applied (by circuits not shown in the drawings) to modify the luminance signal prior to applying that signal to the cathode of the CRT.
  • the respective contributions of the contrast adjustment voltage 19 and sharpness adjustment voltage 20 to the value of the limit control voltage 24 will be determined by the respective values of the resistor 21 and 22. These respective resistor values are selected such as to provide an optimum degree of natural appearance in the final displayed picture throughout various different conditions of contrast and sharpness of that picture, resulting from various different values of the contrast adjustment voltage 19 and sharpness adjustment voltage 20. For example, if the value of the resistor 21 is made smaller than that of the resistor 22, then greater changes will occur in the limit value of amplitude (determined by the diode limiter circuit 5) in response to changes in the contrast adjustment voltage 19 than will occur in response to changes in the sharpness adjustment voltage 20. Thus the respective values of these resistors can be determined such as to ensure that a clear and natural-looking picture will be displayed at all times.
  • an outline compensation apparatus controls a degree of outline enhancement of a displayed picture of a television receiver in accordance with one or both of the levels of a contrast adjustment signal voltage and a sharpness adjustment signal voltage.
  • the invention thus is highly effective in enabling the user of a television receiver to adjust the characteristics of a displayed picture such as to produce a clear and natural-looking picture.
  • limit control voltage 24 in FIG. 2 is generated based on a combination of the contrast adjustment voltage 19 and the sharpness adjustment voltage 20. However it would also be possible to utilize only one of these to derive that limit control voltage 24.
  • velocity modulation based on electromagnetic deflection force applied to the electron beam of a CRT by the velocity modulation coil 8
  • velocity modulation which is based on electrostatic deflection
  • the invention is not limited to an outline compensation apparatus which is based on outline enhancement by means of velocity modulation of an electron beam of a CRT display, but could be adapted for use with a television receiver having some other type of display device such as a liquid crystal display panel, by using an appropriate method of outline enhancement.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
  • Details Of Television Scanning (AREA)
US07/709,871 1990-06-05 1991-06-04 Scanning velocity modulation type enhancement responsive to both contrast and sharpness controls Expired - Lifetime US5164829A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2-148287 1990-06-05
JP2148287A JP2692342B2 (ja) 1990-06-05 1990-06-05 輪郭補償装置

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CA (1) CA2043831C (fr)

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5267028A (en) * 1988-08-26 1993-11-30 Canon Kabushiki Kaisha Solid state image pickup apparatus having luminance control
US5351094A (en) * 1993-01-21 1994-09-27 Funai Electric Co., Ltd. Television receiver with scan velocity modulation being adjusted according to aspect ratio
WO1996005569A1 (fr) * 1994-08-10 1996-02-22 Anderson Brent E Systeme d'identification video aeroporte et procede associe
EP0691786A3 (fr) * 1994-07-05 1996-04-03 Thomson Consumer Electronics Réglage de la modulation de vitesse de balayage en fonction de la netteté sélectionnée
US5532756A (en) * 1994-02-01 1996-07-02 Sony Corporation Color video signal detector and color video signal detecting method
EP0723365A1 (fr) 1995-01-18 1996-07-24 Philips Electronique Grand Public Appareil vidéo à réglage dit de contour
US5600381A (en) * 1994-06-20 1997-02-04 Thomsom Consumer Electronics, Inc. Scan velocity modulation circuit
US6549244B1 (en) * 1998-08-14 2003-04-15 Sony Corporation Scanning speed modulating circuit for picture display
US6816141B1 (en) * 1994-10-25 2004-11-09 Fergason Patent Properties Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US6972805B2 (en) * 2000-02-29 2005-12-06 Koninklijke Philips Electronics N.V. Display of a video signal by means of a line scan
US7064740B2 (en) 2001-11-09 2006-06-20 Sharp Laboratories Of America, Inc. Backlit display with improved dynamic range
US7164284B2 (en) 2003-12-18 2007-01-16 Sharp Laboratories Of America, Inc. Dynamic gamma for a liquid crystal display
US20080024941A1 (en) * 2006-07-31 2008-01-31 Fish William E Method and apparatus for operating electrical machines
US7342592B2 (en) 2004-06-14 2008-03-11 Sharp Laboratories Of America, Inc. System for reducing crosstalk
US7505018B2 (en) 2004-05-04 2009-03-17 Sharp Laboratories Of America, Inc. Liquid crystal display with reduced black level insertion
US7525528B2 (en) 2004-11-16 2009-04-28 Sharp Laboratories Of America, Inc. Technique that preserves specular highlights
US7532192B2 (en) 2004-05-04 2009-05-12 Sharp Laboratories Of America, Inc. Liquid crystal display with filtered black point
US7556836B2 (en) 2004-09-03 2009-07-07 Solae, Llc High protein snack product
US7612757B2 (en) 2004-05-04 2009-11-03 Sharp Laboratories Of America, Inc. Liquid crystal display with modulated black point
US7623105B2 (en) 2003-11-21 2009-11-24 Sharp Laboratories Of America, Inc. Liquid crystal display with adaptive color
US7777714B2 (en) 2004-05-04 2010-08-17 Sharp Laboratories Of America, Inc. Liquid crystal display with adaptive width
US7853094B2 (en) 2006-01-24 2010-12-14 Sharp Laboratories Of America, Inc. Color enhancement technique using skin color detection
US7872631B2 (en) 2004-05-04 2011-01-18 Sharp Laboratories Of America, Inc. Liquid crystal display with temporal black point
US7898519B2 (en) 2005-02-17 2011-03-01 Sharp Laboratories Of America, Inc. Method for overdriving a backlit display
US8050511B2 (en) 2004-11-16 2011-11-01 Sharp Laboratories Of America, Inc. High dynamic range images from low dynamic range images
US8050512B2 (en) 2004-11-16 2011-11-01 Sharp Laboratories Of America, Inc. High dynamic range images from low dynamic range images
US8121401B2 (en) 2006-01-24 2012-02-21 Sharp Labortories of America, Inc. Method for reducing enhancement of artifacts and noise in image color enhancement
US8243004B2 (en) 2003-03-10 2012-08-14 Fergason Patent Properties, Llc Apparatus and method for preparing, storing, transmitting and displaying images
US8395577B2 (en) 2004-05-04 2013-03-12 Sharp Laboratories Of America, Inc. Liquid crystal display with illumination control
US8941580B2 (en) 2006-11-30 2015-01-27 Sharp Laboratories Of America, Inc. Liquid crystal display with area adaptive backlight

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8212936B2 (en) 2004-06-10 2012-07-03 Pioneer Corporation Picture quality control apparatus, method therefor, picture quality processing apparatus, programs for them, and recording medium recording that program therein

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JPH0230276A (ja) * 1988-07-20 1990-01-31 Sanyo Electric Co Ltd 輪郭補正回路
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US4080628A (en) * 1977-03-14 1978-03-21 Zenith Radio Corporation Expanded-signal image enhancement system
JPS61210769A (ja) * 1985-03-14 1986-09-18 Pioneer Electronic Corp 映像再生装置
JPH0230276A (ja) * 1988-07-20 1990-01-31 Sanyo Electric Co Ltd 輪郭補正回路
JPH02249366A (ja) * 1989-03-23 1990-10-05 Matsushita Electric Ind Co Ltd 輪郭補償装置
US5072300A (en) * 1990-08-02 1991-12-10 Thomson Consumer Electronics, Inc. Beam scan velocity modulation apparatus with disabling circuit

Cited By (53)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5267028A (en) * 1988-08-26 1993-11-30 Canon Kabushiki Kaisha Solid state image pickup apparatus having luminance control
US5563657A (en) * 1988-08-26 1996-10-08 Canon Kabushiki Kaisha Solid state image pickup apparatus having improved luminance control
US5351094A (en) * 1993-01-21 1994-09-27 Funai Electric Co., Ltd. Television receiver with scan velocity modulation being adjusted according to aspect ratio
US5532756A (en) * 1994-02-01 1996-07-02 Sony Corporation Color video signal detector and color video signal detecting method
US5600381A (en) * 1994-06-20 1997-02-04 Thomsom Consumer Electronics, Inc. Scan velocity modulation circuit
EP0691786A3 (fr) * 1994-07-05 1996-04-03 Thomson Consumer Electronics Réglage de la modulation de vitesse de balayage en fonction de la netteté sélectionnée
US5587745A (en) * 1994-07-05 1996-12-24 Thomson Consumer Electronics, Inc. Adjustment of scan velocity modulation concurrent with the amount of transition rise time, pre-shoot, and overshoot of a video signal
WO1996005569A1 (fr) * 1994-08-10 1996-02-22 Anderson Brent E Systeme d'identification video aeroporte et procede associe
US7843416B2 (en) 1994-10-25 2010-11-30 Fergason Patent Properties, Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US6816141B1 (en) * 1994-10-25 2004-11-09 Fergason Patent Properties Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US20050093796A1 (en) * 1994-10-25 2005-05-05 Fergason James L. Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US7843417B2 (en) 1994-10-25 2010-11-30 Fergason Patent Properties, Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US20090033607A1 (en) * 1994-10-25 2009-02-05 Fergason James L Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US7843418B2 (en) 1994-10-25 2010-11-30 Fergason Patent Properties, Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US7352347B2 (en) 1994-10-25 2008-04-01 Fergason Patent Properties, Llc Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US20080122771A1 (en) * 1994-10-25 2008-05-29 Fergason James L Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US20080136762A1 (en) * 1994-10-25 2008-06-12 Fergason James L Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
US20080259012A1 (en) * 1994-10-25 2008-10-23 Fergason James L Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching
EP0723365A1 (fr) 1995-01-18 1996-07-24 Philips Electronique Grand Public Appareil vidéo à réglage dit de contour
US6549244B1 (en) * 1998-08-14 2003-04-15 Sony Corporation Scanning speed modulating circuit for picture display
US6972805B2 (en) * 2000-02-29 2005-12-06 Koninklijke Philips Electronics N.V. Display of a video signal by means of a line scan
US7064740B2 (en) 2001-11-09 2006-06-20 Sharp Laboratories Of America, Inc. Backlit display with improved dynamic range
US7499017B2 (en) 2001-11-09 2009-03-03 Sharp Laboratories Of America, Inc. Backlit display with improved dynamic range
US7505028B2 (en) 2001-11-09 2009-03-17 Sharp Laboratories Of America, Inc. Backlit display with improved dynamic range
US7505027B2 (en) 2001-11-09 2009-03-17 Sharp Laboratories Of America, Inc. Backlit display with improved dynamic range
US7714830B2 (en) 2001-11-09 2010-05-11 Sharp Laboratories Of America, Inc. Liquid crystal display backlight with level change
US7675500B2 (en) 2001-11-09 2010-03-09 Sharp Laboratories Of America, Inc. Liquid crystal display backlight with variable amplitude LED
US8378955B2 (en) 2001-11-09 2013-02-19 Sharp Laboratories Of America, Inc. Liquid crystal display backlight with filtering
US7737936B2 (en) 2001-11-09 2010-06-15 Sharp Laboratories Of America, Inc. Liquid crystal display backlight with modulation
US7573457B2 (en) 2001-11-09 2009-08-11 Sharp Laboratories Of America, Inc. Liquid crystal display backlight with scaling
US8243004B2 (en) 2003-03-10 2012-08-14 Fergason Patent Properties, Llc Apparatus and method for preparing, storing, transmitting and displaying images
US9847073B2 (en) 2003-03-10 2017-12-19 Fergason Licensing Llc Apparatus and method for preparing, storing, transmitting and displaying images
US9881588B2 (en) 2003-03-10 2018-01-30 Fergason Licensing Llc Apparatus and method for preparing, storing, transmitting and displaying images
US7623105B2 (en) 2003-11-21 2009-11-24 Sharp Laboratories Of America, Inc. Liquid crystal display with adaptive color
US7164284B2 (en) 2003-12-18 2007-01-16 Sharp Laboratories Of America, Inc. Dynamic gamma for a liquid crystal display
US7777714B2 (en) 2004-05-04 2010-08-17 Sharp Laboratories Of America, Inc. Liquid crystal display with adaptive width
US7505018B2 (en) 2004-05-04 2009-03-17 Sharp Laboratories Of America, Inc. Liquid crystal display with reduced black level insertion
US7612757B2 (en) 2004-05-04 2009-11-03 Sharp Laboratories Of America, Inc. Liquid crystal display with modulated black point
US8395577B2 (en) 2004-05-04 2013-03-12 Sharp Laboratories Of America, Inc. Liquid crystal display with illumination control
US7872631B2 (en) 2004-05-04 2011-01-18 Sharp Laboratories Of America, Inc. Liquid crystal display with temporal black point
US7532192B2 (en) 2004-05-04 2009-05-12 Sharp Laboratories Of America, Inc. Liquid crystal display with filtered black point
US7342592B2 (en) 2004-06-14 2008-03-11 Sharp Laboratories Of America, Inc. System for reducing crosstalk
US7556836B2 (en) 2004-09-03 2009-07-07 Solae, Llc High protein snack product
US8050512B2 (en) 2004-11-16 2011-11-01 Sharp Laboratories Of America, Inc. High dynamic range images from low dynamic range images
US8050511B2 (en) 2004-11-16 2011-11-01 Sharp Laboratories Of America, Inc. High dynamic range images from low dynamic range images
US7525528B2 (en) 2004-11-16 2009-04-28 Sharp Laboratories Of America, Inc. Technique that preserves specular highlights
US7898519B2 (en) 2005-02-17 2011-03-01 Sharp Laboratories Of America, Inc. Method for overdriving a backlit display
US8121401B2 (en) 2006-01-24 2012-02-21 Sharp Labortories of America, Inc. Method for reducing enhancement of artifacts and noise in image color enhancement
US7853094B2 (en) 2006-01-24 2010-12-14 Sharp Laboratories Of America, Inc. Color enhancement technique using skin color detection
US9143657B2 (en) 2006-01-24 2015-09-22 Sharp Laboratories Of America, Inc. Color enhancement technique using skin color detection
US7633259B2 (en) * 2006-07-31 2009-12-15 General Electric Company Method and apparatus for operating electrical machines
US20080024941A1 (en) * 2006-07-31 2008-01-31 Fish William E Method and apparatus for operating electrical machines
US8941580B2 (en) 2006-11-30 2015-01-27 Sharp Laboratories Of America, Inc. Liquid crystal display with area adaptive backlight

Also Published As

Publication number Publication date
JPH0440171A (ja) 1992-02-10
JP2692342B2 (ja) 1997-12-17
CA2043831A1 (fr) 1991-12-06
CA2043831C (fr) 1995-07-25

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